Error handling in Portal standard forms

Question

I have a customer who needs to validate input on a Form Based on a Table (standard component). They have tried code, as shown below, as a PLSQL handler on a Save button. This example can obviously be solved with JavaScript validation on the client, but they have similar requirements for validation on DB level.
If procedure call 1) in the if statement is used, nothing happens. If procedure call 2) is used, it is executed in a new page as a standard error Oracle Portal error message.
declare
v_sender VARCHAR2(1000);
v_sender_id NUMBER;
begin
v_sender := p_session.get_value_as_VARCHAR2(
p_block_name => 'DEFAULT',
p_attribute_name => 'A_SENDER');
v_sender_id := p_session.get_value_as_NUMBER(
p_block_name => 'DEFAULT',
p_attribute_name => 'A_SENDER_ID');
insert into hd (number, text) values (hd_seq.nextval,
'step 3 v_sender = ' || v_sender ||
' v_sender_id = ' || v_sender_id);
if v_sender_id >= 100 then
1) Custom error handling, does not display:
show_error('Error message');
2) Error handling is displayed, but as a standard error:
raise_application_error(-20000, 'SenderID must be smaller than 100.');
else
doInsert;
end if;
end;
The customer has two questions:
Why does the custom procedure in 1) "show_error" not execute, and if it does, why does it not display? show_error works and the if statement is entered.
Is it possible to take control of Portals error handling on standard components (forms etc.), to show custom error messages with the style used on the component/page instead of the standard Error: ORA- ....etc. as Portal displays it?
Customer needs reply asap. Please reply directly. Any help will be much appreciated!
Kind regards
Jakob Lund

Answer 1

Jacob,
Try following:
declare
v_sender VARCHAR2(1000);
v_sender_id NUMBER;
begin
v_sender := p_session.get_value_as_VARCHAR2(
p_block_name => 'DEFAULT',
p_attribute_name => 'A_SENDER');
v_sender_id := p_session.get_value_as_NUMBER(
p_block_name => 'DEFAULT',
p_attribute_name => 'A_SENDER_ID');
insert into hd (number, text) values (hd_seq.nextval,
'step 3 v_sender = ' || v_sender ||
' v_sender_id = ' || v_sender_id);
if v_sender_id >= 100 then
p_session.set_value(
p_block_name => "_block",
p_attribute_name => '_STATUS',
p_value => 'Sender ID must be less than 100!');
-- return to your form with status message set
-- and all fields filled with recent values
return;
end if;
end;
-- This point is reached only if validation is OK
doInsert;
Regards,
Henn